山东平邑归来庄金矿床原生晕三维特征及深部找矿启示OA

The Guilaizhuang gold deposit in Pingyi County,Shandong Province,is the first documented tellurium-gold type epithermal deposit in China.As its deep and peripheral areas retain significant prospecting potential,establishing an effective exploration model is critical.In this study,672 primary halo samples collected from 58 exploration drill holes at the Guilaizhuang gold deposit were analyzed.A three-dimensional primary halo analysis method was adopted to overcome the limitations of traditional two-dimensional approaches.Through multivariate statistical analysis,primary halo indicator elements were identified,and a 3D geochemical anomaly model was constructed to reveal the characteristics of primary halos and their correlation with mineralization to evaluate the prospectivity for concealed deep ore bodies.The results show that:① The Guilaizhuang gold deposit exhibits an axial zoning sequence of As-Sb-Se(frontal halo),Ag-Au-Te-Pb-Zn(proximal halo),and Mo-V(rear halo).Significantly,rear halo elements(Mo,V)are enriched at the top of the orebody clusters,representing a distinctive"reverse zoning"phenomenon.② Gold-indicating element ratios(Ag/Au,As/Sb and Zn/Pb)display NE-SW directional zoning,consistent with the strike of the structural-cryptoexplosive breccia zone controlled by the Guilaizhuang F1 fault.③ The frontal-rear halo multiplicative ratio(As×Sb×Se)/(Mo×V)exhibits anomalous inflection points at elevations of-750 m and-1700 m,indicating the presence of concealed orebodies at depth.The findings suggest that mineralization at Guilaizhuang involved the superposition of multi-stage hydrothermal fluids.Ore-forming fluids originating from the deep southwest part of the deposit migrated upward along the structural conduits formed by the Guilaizhuang F1 fault to the near-surface,resulting in the formation of structural-cryptoexplosive breccia-hosted and quasi-layered carbonate-hosted gold orebodies.It is inferred that the deep prospecting potential of the deposit remains promising,with the deep southern region below an elevation of-750 m along exploration line 35 identified as a priority target zone for further exploration.